Liquid and semi-liquid dispensers are widely used in various industries. In the food and beverage industry, certain products are provided in partially frozen, semi-frozen or frozen states. Sometimes, the products are called “slush.” For purpose of the present disclosure, the term “semi-frozen beverage dispenser” is meant to include beverage dispensers that produce partially frozen, semi-frozen or frozen products, whether they are postmix (separate ingredients reconstituted into a final product in the machine) or premix (prepackaged with the final constituents), carbonated or non-carbonated. Sometimes, the machines are referred to as a “granita” machine. An exemplary semi-frozen beverage dispenser for purpose of the present disclosure is a frozen carbonated beverage (FCB) machine.
FCB machines known in the art generally pump potable water through a carbonator tank that contains pressurized carbon dioxide in order to make carbonated water. The carbonated water and at least one concentrated syrup are then conducted to the same mixing container at a particular ratio, before further delivered to a freezing cylinder. A sampling valve is sometimes provided before the mixture of the carbonated water and the syrup reaches the mixing container to provide a chance for sampling. An evaporator coil or a similar refrigeration mechanism is provided to chill the contents in the freezing cylinder to a slush form. Some form of a scraper, blade or auger rotates or otherwise moves to scrape the thin frozen layer from the internal surface of the cylinder and to maintain flavor consistency within the slush.
Existing mechanisms for regulating the water to syrup ratio (brix) typically involve the use of a ceramic sleeve fitted over a piston for the syrup conduit. When the mixing container needs to be refilled, both the syrup conduit and the water conduit are opened simultaneously or substantially so to allow syrup and water to flow into the mixing container. An operator mechanically adjusts the spring tension that in turn changes the clearance between the sleeve and the piston in order to adjust the syrup flow rate.
The clearance between the sleeve and the piston can be as little as 0.01 inch (0.25 mm) in radius. As a result, the system is prone to brix control failure when particulates get logged in the clearance. Also, panels have to be removed in order to mechanically access the point for adjusting the clearance. In view of the above, there is a strong need for a more reliable and less cumbersome mechanism for regulating the water to syrup ratio in a semi-frozen beverage dispenser.